# AssemblyAI vs Gradium

AssemblyAI records 453,591 monthly visits with -6.9% month-over-month growth and Freemium, Contact for Pricing pricing. Gradium records 126,416 monthly visits with +128.7% growth and Freemium, Contact for Pricing pricing.

| Metric | [AssemblyAI](https://openaitools.app/tool/assemblyai) | [Gradium](https://openaitools.app/tool/gradium) |
| :--- | :--- | :--- |
| Website URL | https://www.assemblyai.com | https://gradium.ai |
| Categories | AI Speech-to-Text, AI Transcription, AI Speech Recognition, AI Developer Tools | AI Text-to-Speech, AI Speech-to-Text, AI Voice Cloning, AI API |
| Pricing Model | Freemium, Contact for Pricing | Freemium, Contact for Pricing |
| Monthly Visits | 453,591 | 126,416 |
| MoM Growth Rate | -6.9% | +128.7% |
| Primary Market | Brazil | France |
| Direct Visits | 281,472 | 27,158 |
| Review Score | 4.6 | 4.5 |
| Saved Count | 9 | 0 |
| Supported Platforms | Website | Website |

## AssemblyAI

AssemblyAI builds speech AI models and the infrastructure to run them, aimed at developers and product teams adding voice to an application. Its core offering is speech-to-text: an asynchronous API for pre-recorded audio, a realtime API for streaming and voice agents, and a synchronous API for short clips and dictation. The company's flagship accuracy model is marketed as top of independent benchmarks, with strong speaker diarization and native code-switching across dozens of languages.

On top of transcription, AssemblyAI offers a Speech Understanding API that layers tasks such as summarization, sentiment, topic detection, PII redaction, content moderation and guardrails onto transcripts. It has also released its first text-to-speech model, AssemblyAI-TTS-1, built for voice agents on live calls, plus an LLM Gateway for routing model calls and a Dictation API. Models can run on AssemblyAI's managed inference cloud, or self-hosted in a customer's own VPC or on-premises environment.

Pricing is pay-as-you-go after a free trial: for example, pre-recorded transcription is billed per audio hour, with optional add-ons such as speaker diarization, keyterms prompting and medical or veterinary modes priced separately. Enterprise plans offer custom rate limits, higher concurrency and compliance features including SOC 2 Type 2, HIPAA and GDPR.

**Pricing & Plans:** Free trial to start, then pay-as-you-go per audio hour and per add-on feature — for example around $0.15/hr for the Universal-2 model and around $0.21/hr for the more accurate Universal-3.5 Pro model, with extras like diarization billed individually. Enterprise and custom-rate-limit plans are available via sales.

- **Async, realtime and sync speech-to-text:** Choose pre-recorded transcription for files, a realtime API for live streams and voice agents, or a synchronous endpoint for short clips and dictation.
- **Audio intelligence and Speech Understanding:** Layer summarization, sentiment, topic detection, PII redaction, content moderation and guardrails onto transcripts without building your own models.
- **Text-to-speech for voice agents:** AssemblyAI-TTS-1 is trained on real phone calls for natural, low-latency speech, targeted at IVR and voice-agent use cases.
- **High accuracy with diarization:** Flagship models emphasise exact transcription, speaker labels and native code-switching across many languages, supported by published benchmarks.
- **Flexible deployment:** Run models on AssemblyAI's managed cloud with unlimited concurrency, or self-host in your own VPC or on-prem for full data control.

**Strengths:** One API family covering transcription, understanding and text-to-speech; Transparent per-hour pay-as-you-go pricing with a free trial; Self-hosting option for teams with strict data-residency requirements; Strong accuracy and diarization performance backed by published benchmarks

**Limitations:** Costs scale with volume and add-ons can raise the effective per-hour rate; Some advanced features are model-specific and not available on every model; Heavier product surface than a simple transcription API may be overkill for basic needs

[Profile (Markdown)](https://openaitools.app/tool/assemblyai.md)

## Gradium

Gradium targets teams building conversational voice agents, telephony bots, and real-time translation experiences where latency decides whether a product feels natural. Its model lineup covers the full loop: text-to-speech for synthesis, speech-to-text for transcription, live voice-to-voice translation, instant cloning from a short audio sample, pro cloning for production-grade custom voices, and voice design that creates a brand-new voice from a text description alone.

The platform is API-first, with SDKs for Python and Rust, WebSocket streaming, semantic voice activity detection, custom vocabularies, code-switching support, and integrations such as LiveKit and Pipecat so teams can drop it into existing agent stacks. Gradium also ships Phonon, an open on-device TTS model that can run offline, which matters for privacy-sensitive or embedded deployments.

Pricing is credit-based across five self-serve tiers plus enterprise. Credits map to usage: text-to-speech costs 1 credit per character, speech-to-text 3 credits per second, speech-to-text translation 4 credits per second, and speech-to-speech translation 30 credits per second. Higher tiers unlock commercial use, more custom voices, pro clones, and better concurrency, while enterprise adds dedicated inference, on-premises deployment, and options such as Baseten or SageMaker endpoints.

**Pricing & Plans:** Free tier with 45k credits per month. Paid plans run $12/mo (XS), $39/mo (S), $312/mo (M), and $1,480/mo (L) on monthly billing, with yearly billing giving one month free. Usage is credit-based (1 credit per TTS character, 3 credits per STT second, 30 credits per second for speech-to-speech translation). Enterprise pricing is custom.

- **Ultra-low-latency voice models:** Text-to-speech, speech-to-text, and live speech-to-speech translation reach roughly 50 ms to first audio, tuned for conversational agents rather than batch processing.
- **Tiered voice cloning and voice design:** Clone a voice from a short sample for everyday use, move up to pro cloning for production quality, or generate a brand-new voice from a text description.
- **Developer-first API and SDKs:** WebSocket streaming, Python and Rust SDKs, custom vocabulary, semantic VAD, and code-switching support make integration straightforward for agent builders.
- **Open on-device TTS with Phonon:** Phonon is Gradium's openly available TTS model that runs on-device for offline or privacy-sensitive deployments.
- **Scaling and deployment options:** Gradium handles concurrency tiers for growing traffic and supports dedicated inference, on-premises deployment, and Baseten or SageMaker endpoint hosting.

**Strengths:** Very low latency tuned specifically for live voice agents rather than offline batch jobs; Full voice stack in one API: TTS, STT, translation, cloning, and voice design; Genuine free tier (45k credits/month) and low $12/mo entry point for prototyping; Enterprise-grade options including on-premises deployment, data residency, and an open on-device TTS model

**Limitations:** Credit-based pricing is harder to forecast than flat per-seat plans, and unused plan credits expire monthly; Pro voice cloning and higher concurrency sit behind the larger monthly tiers; Feature depth varies by plan, so commercial use requires at least the XS tier

[Profile (Markdown)](https://openaitools.app/tool/gradium.md)

## Frequently Asked Questions

### How do AssemblyAI and Gradium compare in monthly traffic?

AssemblyAI has 453,591 monthly visits, while Gradium has 126,416. Traffic estimates describe audience size, not product quality.

### How do their growth rates compare?

AssemblyAI has a month-over-month growth rate of -6.9%; Gradium has +128.7%.

### How does pricing compare?

AssemblyAI: Freemium, Contact for Pricing. Free trial to start, then pay-as-you-go per audio hour and per add-on feature — for example around $0.15/hr for the Universal-2 model and around $0.21/hr for the more accurate Universal-3.5 Pro model, with extras like diarization billed individually. Enterprise and custom-rate-limit plans are available via sales. Gradium: Freemium, Contact for Pricing. Free tier with 45k credits per month. Paid plans run $12/mo (XS), $39/mo (S), $312/mo (M), and $1,480/mo (L) on monthly billing, with yearly billing giving one month free. Usage is credit-based (1 credit per TTS character, 3 credits per STT second, 30 credits per second for speech-to-speech translation). Enterprise pricing is custom.

## Alternatives

| # | Tool Name | Monthly Visits | MoM Growth Rate | Pricing Model | Summary | Profile (Markdown) |
| :--- | :--- | :--- | :--- | :--- | :--- | :--- |
| 1 | [OpenAI Platform](https://openaitools.app/tool/openai) | 234,678,639 | -9.6% | Paid | Enterprise developer platform and API for deploying GPT-6 Astra, Sol, Luna, and realtime multimodal agents. | [.md](https://openaitools.app/tool/openai.md) |
| 2 | [ElevenLabs](https://openaitools.app/tool/elevenlabs-io) | 42,396,771 | +26.1% | Freemium, Paid, Contact for Pricing | AI audio platform for speech, agents, music and dubbing | [.md](https://openaitools.app/tool/elevenlabs-io.md) |
| 3 | [Fish Audio](https://openaitools.app/tool/fish-speech) | 8,557,159 | +1.6% | Freemium | Studio-grade AI text to speech and voice cloning | [.md](https://openaitools.app/tool/fish-speech.md) |
| 4 | [Groq](https://openaitools.app/tool/groq) | 3,987,936 | +10% | Paid | Ultra-fast AI inference on the LPU and LPX platform | [.md](https://openaitools.app/tool/groq.md) |
| 5 | [Cartesia](https://openaitools.app/tool/cartesia-ai) | 1,782,707 | +49.7% | Contact for Pricing | Real-time voice AI models and agents you can build on | [.md](https://openaitools.app/tool/cartesia-ai.md) |
| 6 | [Deepgram Voice AI](https://openaitools.app/tool/deepgram-voice-ai) | 863,852 | +31.8% | Free Trial | Real-time speech-to-text, text-to-speech and voice agents in one API platform | [.md](https://openaitools.app/tool/deepgram-voice-ai.md) |
| 7 | [Vapi](https://openaitools.app/tool/vapi) | 662,301 | -11.4% | Freemium | Build, test, and deploy production-grade voice AI agents over API | [.md](https://openaitools.app/tool/vapi.md) |
| 8 | [Noiz AI](https://openaitools.app/tool/noiz-ai) | 441,445 | -30.1% | Paid | Clone voice, control emotion, and create lifelike speech. | [.md](https://openaitools.app/tool/noiz-ai.md) |
| 9 | [Soniox](https://openaitools.app/tool/soniox) | 335,647 | +2.2% | Paid | One speech AI API for recognition, generation, and translation in 60+ languages | [.md](https://openaitools.app/tool/soniox.md) |
| 10 | [Gladia](https://openaitools.app/tool/gladia) | 232,451 | +6.4% | Freemium, Contact for Pricing | Speech-to-text and audio intelligence API for production voice products | [.md](https://openaitools.app/tool/gladia.md) |

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Source: https://openaitools.app/compare/assemblyai-vs-gradium

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